|
|
| (19 intermediate revisions by the same user not shown) |
| Line 1: |
Line 1: |
| − | == Literary Python for Beginners ==
| + | Next pages: [[Python_for_beginners/collections|Collections]] // [[Python_for_beginners/loops_and_conditions|Loops and Conditions]] // [[Python_for_beginners/anthology|Create anthology]] |
| | | | |
| − | === LETTER * WORD * SENTENCE === | + | '''=== VARIABLES ===''' |
| | | | |
| | * Introduction to the objects string & list with their different attributes | | * Introduction to the objects string & list with their different attributes |
| − | * uses the shell or integrated development environment | + | * uses the shell |
| | | | |
| − | ** run python 2.7 – installed by default on all platforms
| |
| | | | |
| − | $ python
| + | '''# USING STRINGS''' |
| | | | |
| − | >>>
| + | A string is a chain of characters / text and can contain any type of characters |
| | | | |
| | + | A string is defined by " " |
| | | | |
| − | ** install python idle 2.7 – ways to interact with Python: shell + editor
| |
| | | | |
| | + | '''* Write text using STRING''' |
| | | | |
| | + | >>> print("La Cambre") |
| | | | |
| − | '''# USING STRINGS'''
| + | ** Exercise: Write your name''' |
| | | | |
| − | A string is a chain of characters / text and can contain any type of characters
| + | >>> ... |
| | | | |
| − | A string is defined by " "
| |
| | | | |
| − | '''* write letter using STRING''' | + | '''* Adding text''' |
| | | | |
| − | >>> "a" | + | >>> print("Brussels"+"Paris") |
| | | | |
| − | '''* write several letters'''
| + | >>> print("Brussels "+"Paris") |
| | | | |
| − | >>> "a, b, c, d"
| + | ** Exercise: Write your address''' |
| | | | |
| − | '''* write combinations'''
| |
| | | | |
| − | >>> "a" + "b"
| + | '''* Composing a sentence''' |
| | | | |
| − | >>> 3 | + | >>> print("Paris", "to", "London", "via", "Brussels") |
| | | | |
| − | >>> "a" + "and" + "b" | + | >>> print("Paris to London via Brussels") |
| | | | |
| − | >>> "a" + " and " + "b"
| + | ** Exercise: Write your favourite expression''' |
| | | | |
| − | >>> "a" + "+ " + 3 + " is a3" ***
| |
| | | | |
| − | >>> 3*3
| + | '''* Multiply''' |
| | | | |
| − | >>> "a" + "+ " + "3" + " is a3" | + | >>> print(3*3) |
| | | | |
| − | >>> 3 * "algolit" + " in wtc25" | + | >>> 3 * "algolit" + " in Brussels" |
| | | | |
| − | | + | ** Exercise: Write 'I write the alphabet' 3 times. |
| − | ** Exercise: Write 'I write the alphabet 3 times.' | |
| | | | |
| | Note: there are always different possible solutions | | Note: there are always different possible solutions |
| | | | |
| | | | |
| − | '''* write string as variable''' | + | '''* Write a string as a variable''' |
| | | | |
| | ** Avoids having to retype your string each time you use it | | ** Avoids having to retype your string each time you use it |
| Line 62: |
Line 59: |
| | >>> letter = "a" | | >>> letter = "a" |
| | | | |
| − | >>> print letter | + | >>> print(letter) |
| | | | |
| | >>> word = "algolit" | | >>> word = "algolit" |
| | | | |
| − | >>> print word | + | >>> print(word) |
| | | | |
| − | >>> sentence = "I learn to read and write again at wtc25" | + | >>> sentence = "I learn to read and write again in Python." |
| | | | |
| − | >>> print sentence, letter | + | >>> print(sentence, letter) |
| | | | |
| − | ** Exercise: print your letter, word, sentence | + | ** Exercise: Print your letter, word, sentence |
| | | | |
| | | | |
| − | '''* add punctuation''' | + | '''* Add punctuation''' |
| | | | |
| − | >>> print letter + " " + word + " " + sentence + "." | + | >>> print(letter + " " + word + " " + sentence + ".") |
| | | | |
| − | >>> print letter + "! " + word + "? " + sentence + "." | + | >>> print(letter + "! " + word + "? " + sentence + ".") |
| | | | |
| | >>> letter = "i" | | >>> letter = "i" |
| Line 88: |
Line 85: |
| | | | |
| | | | |
| − | '''* calculate!''' | + | '''* Calculate!''' |
| | | | |
| | ** the length of the string | | ** the length of the string |
| | | | |
| − | >>> len(letter) | + | >>> print(len(letter)) |
| − | >>> len(word)
| + | >>> print(len(word)) |
| − | >>> len(sentence)
| + | >>> print(len(sentence)) |
| − | | + | >>> print(len(word))+2) |
| − | | |
| − | ** we can also consider the letter/word/sentence as fields or grids, in which each letter occupies a specific position
| |
| − | | |
| − | Note: computer starts to count from 0
| |
| − | | |
| − | >>> word[0]
| |
| − | >>> word[3]
| |
| − | | |
| − | ** Exercise: what is the middle letter of your sentence?
| |
| − | | |
| − | | |
| − | '''* Slicing and concatenating strings in order to select letters & compose new words'''
| |
| − | | |
| − | ** find last letter
| |
| − | | |
| − | >>> zin[-1]
| |
| − | | |
| − | ** find last but one letter
| |
| − | | |
| − | >>> word[-2]
| |
| − | | |
| − | ** find first two letters
| |
| − | | |
| − | >>> word[0:2]
| |
| − | | |
| − | or
| |
| − | | |
| − | >>> word[:2]
| |
| − | | |
| − | ** find 3 letters in the middle
| |
| − | | |
| − | >>> word[2:5]
| |
| − | | |
| − | ** find from 3rd letter till end
| |
| − | | |
| − | >>> word[2:]
| |
| − | | |
| − | ** Exercise: If the word is "solidarity" is, what do you read here?
| |
| − | word[:5] + word[3:]
| |
| − | | |
| − | ** Exercise: rewrite the word as 'liquidity', using slicing
| |
| − | | |
| − | | |
| − | '''* write with capitals'''
| |
| − | | |
| − | >>> print letter.lower() | |
| − | | |
| − | >>> print sentence.upper()
| |
| − | | |
| − | | |
| − | '''* write first word of sentence with capital letter'''
| |
| − | | |
| − | >>> print sentence.capitalize()
| |
| − | | |
| − | | |
| − | '''* note the difference'''
| |
| − | | |
| − | >>> sentence.title()
| |
| − | | |
| − | >>> word.title() | |
| − | | |
| − | | |
| − | [[Some_Python_Vocabulary]]
| |
| − | | |
| − | [[Loops_and_conditions]]
| |
| − | | |
| − | [[Anthology]]
| |
| − | | |
| − | # Some Python vocabulary
| |
| − | ## the string or string object is a MODULE in Python
| |
| − | | |
| − | # A MODULE simply is a file, which contains Python statements.
| |
| − | Normally among these there are:
| |
| − | * definition statements -> the execution of the module defines some functions
| |
| − | * class statements -> the execution of the module defines some classes.
| |
| − | A module may also contain names (variables) and other directly executable
| |
| − | Python statements.
| |
| − | # you can write your own definitions/functions and save them I a file that you can import into another python-file
| |
| − | # such a document is an external module, called at the beginning of a script using 'import name_module'
| |
| − | # CLASSES contain METHODS, a series of FUNCTIONS that are part of a class
| |
| − | # the string-module contains classes with functions that allow you to calculate the length of the sting, slice etc
| |
| − | | |
| − | # Anything in Python can be an OBJECT, because it can be assigned to a variable or can be an argument (input) for a function - OBJECT ORIENTED PROGRAMMING
| |
| − | | |
| − | # an ATTRIBUTE is is a way to move from one object to the other
| |
| − | # “Apply the power of the almighty dot” - objectname.attributename – and magic!
| |
| − | | |
| − | # !!! to know the attributes of an object: dir()
| |
| − | # This means the object has a method called __dir__()
| |
| − | # dir() calls this method and prints the list of attributes
| |
| − | | |
| − | dir(letter)
| |
| − | | |
| − | # choose for example .endswith()
| |
| − | sentence = "This is so exciting!"
| |
| − | suffix = "ing!"
| |
| − | print sentence.endswith(suffix) | |
| − | len(sentence) | |
| − | print sentence.endswith(suffix,20) -> False
| |
| − | print sentence.endswith(suffix,16) -> True
| |
| − | print sentence.endswith(suffix,16,20) -> True
| |
| − | | |
| − | # Exercise: think of formula that gives TRUE for suffix 'is'
| |
| − | # a long string can be annotated using 3 """ a lot of words """
| |
| − | # if you have a very long string, you better use:
| |
| − | very_long_string = (
| |
| − | "For a long time I used to go to bed early. Etc etc …."
| |
| − | )
| |
| − | | |
| − | ### From STRINGS to LISTS
| |
| − | | |
| − | # DISADVANTAGE fo STRINGS: they're immutable
| |
| − | # that is the reason you want to change your string into a list
| |
| − | sentence.split()
| |
| − | # and save it as a new variable
| |
| − | list_words = sentence.split()
| |
| − | | |
| − | # some of the attributes of string can be used for lists
| |
| − | # Exercise: which previously mentioned attributes function for lists?
| |
| − | | |
| − | # change a list
| |
| − | list_words[3] = "wtc25"
| |
| − | print list_words | |
| − | | |
| − | # remove words
| |
| − | list_words[2:3] = []
| |
| − | note: list_words[2] = [] → this removes your 3rd element and replaces it by an empty sublist ('nested list')
| |
| − | | |
| − | # put back words
| |
| − | list_words[2:3] = ["so", "exciting"]
| |
| − | | |
| − | # you can shorten a list
| |
| − | list_words[-3:]
| |
| − | # and save the shortened list into a new variable – the old continues to exist
| |
| − | yezzzz = list_words[-3:]
| |
| − | | |
| − | # you can combine lists, group two in one
| |
| − | text = [list_words, yezzzz]
| |
| − | # and you can call an element of a sublist
| |
| − | word = text[1][2]
| |
| − | | |
| − | # you can concatenate lists, merge two into one
| |
| − | print list_words + yezzzz
| |
| − | poem = list_words + yezzzz
| |
| − | | |
| − | # you can add words to your list
| |
| − | poem.append("is")
| |
| − | print poem
| |
| − | | |
| − | # you can sort your list alphabetically
| |
| − | poem.sort()
| |
| − | | |
| − | | |
| − | | |
| − | # you transform your list into a string again
| |
| − | " ".join(poem)
| |
| − | # detail: the whitespace / try without
| |
| − | " ".join(poem) + "?"
| |
| − | | |
| − | # you can empty your list // we have a brand new sheet of paper!!
| |
| − | poem[:] = []
| |
| − | | |
| − | | |
| − | | |
| − | ### LOOPS & CONDITIONS
| |
| − | | |
| − | # using scripts (modules)
| |
| − | # shell is ok to try out lines of code, but for longer bits we use script, or module
| |
| − | # save file as .py
| |
| − | #!/usr/bin/env python
| |
| − | # -*- coding: utf-8 -*-
| |
| − | | |
| − | | |
| − | # REMIX SONG using STRING, LIST and FOR, IN, IF, WHILE
| |
| − | | |
| − | # Prince, Purple Rain
| |
| − | song = (
| |
| − | “I never meant to cause you any sorrow\n
| |
| − | ”
| |
| − | “I never meant to cause you any pain
| |
| − | \n”
| |
| − | “I only wanted to one time to see you laughing
| |
| − | \n”
| |
| − | “I only wanted to see you\n
| |
| − | ”
| |
| − | “Laughing in the purple rain
| |
| − | .”
| |
| − | )
| |
| − | | |
| − | # transform string in list of words
| |
| − | song = song.split()
| |
| − | | |
| − | # double all words of list and print again as song
| |
| − | remix1 = [word*2 for word in song]
| |
| − | print(" ".join(remix1))
| |
| − | remix1 = remix1[:16]
| |
| − | print(" ".join(remix1))
| |
| − | | |
| − | ## FOR, IN, IF
| |
| − | # rewrite the songs with the words that count more than 4 letters
| |
| − | remix2 = [word for word in song if len(word) <= 4]
| |
| − | remix2 = "°*@".join(remix2)
| |
| − | print(remix2)
| |
| − | | |
| − | # transform all letters of song in lowercaps
| |
| − | remix2 = remix2.lower()
| |
| − | | |
| − | # Capitalize the song and end with a dot // Hèhè, a new sentence!
| |
| − | print(remix2.capitalize() + ".")
| |
| − | | |
| − | # print a list of words of the song + next to each word its length
| |
| − | for word in song:
| |
| − | print(word, len(word))
| |
| − | | |
| − | | |
| − | | |
| − | | |
| − | # print a list of words of the song + next to each word its position in the sentence
| |
| − | for position in range(len(song)):
| |
| − | print position, song[position]
| |
| − | | |
| − | # rewrite song by copying words with r to the beginning of the song
| |
| − | | |
| − | for word in song[:]: # Loop over a copy of the list
| |
| − | if "r" in word:
| |
| − | song.insert(0, word)
| |
| − | print("\n".join(song))
| |
| − | | |
| − | # create an Anaerobe of the song (remove all r's)
| |
| − | http://oulipo.net/fr/contraintes/anaerobie
| |
| − | song = [woord.replace("r","") if "r" in word else word for word in song]
| |
| − | print(song)
| |
| − | song = " \n".join(song)
| |
| − | | |
| − | # Exercise: remove letter 't' and rewrite song using capitals, comma's and hard returns
| |
| − | | |
| − | | |
| − | # WHILE
| |
| − | # A while loop statement in Python programming language repeatedly executes a target statement
| |
| − | as long as a given condition is true.
| |
| − | | |
| − | # Print your song 9 times
| |
| − | amount = 0
| |
| − | while (amount < 10):
| |
| − | print(song)
| |
| − | amount = amount + 1
| |
| − | else:
| |
| − | print "Python can also be a printing factory!"
| |
| − | | |
| − | # The reader can decide how many times she would like to see the song
| |
| − | nbr = raw_input("Give a number :")
| |
| − | amount = 0
| |
| − | while (amount < 5):
| |
| − | print gedicht
| |
| − | amount = amount + 1
| |
| − | else:
| |
| − | print "Python can also be a printing factory!"
| |
| − | | |
| − | | |
| − | # write your text to a file
| |
| − | with open('song.txt', 'a') as f:
| |
| − | f.write("title song" + "\n" + song)
| |
| − | | |
| − | ### TEXT
| |
| − | | |
| − | # you can print any text file
| |
| − | # note: in this case the text is in the same folder as the script, otherwise adapt path
| |
| − | with open('peter_rabbit.txt') as f:
| |
| − | for line in f:
| |
| − | print line
| |
| − | | |
| − | # now you can call operations on this text
| |
| − | new_text = []
| |
| − | with open('peter_rabbit.txt') as f:
| |
| − | for line in f:
| |
| − | for word in line:
| |
| − | if len(word) >= 5:
| |
| − | newtext.append(word)
| |
| − | print(“ “.join(new_text))
| |
| − | | |
| − | | |
| − | # remove punctuation
| |
| − | import string
| |
| − | def remove_punct(f):
| |
| − | tokens = (' '.join(line.replace('\n', '') for line in f)).lower()
| |
| − | for c in string.punctuation:
| |
| − | tokens= tokens.replace(c," ")
| |
| − | return tokens
| |
| − | | |
| − | tokens = remove_punct(f)
| |
| | | | |
| − | # random choice & shuffle
| + | ** and more |
| − | from random import choice, shuffle
| |
| − | names = [peter, benjamin, flopsy, tod, tom, samuel, pie, ginger, moppet, nutkin, timmy, tailor, johnny, mice, tittlemouse, tiggy, rabbit, jemima, jeremy, robinson, pigling]
| |
| | | | |
| − | def select(names):
| + | a_number = len(word)+2 |
| − | name = choice(names)
| + | print(a_number) |
| − | return name
| + | a_number += 3 |
| | + | print(a_number) |
| | | | |
| − | mix = shuffle(names)
| + | ** Exercise: Compose a sentence word by word, specifying each word as a variable. The length of the sentence is 20. |
| | | | |
| − | # proposal to publish an anthology as a pdf
| |
| − | * play with search for words in texts with certain suffixes from texts, remove letters
| |
| − | * write new text to file
| |
| | | | |
| − | * once all files are finished: | + | '''What you've learned''' |
| − | $ cat partfilename* > outputfilename
| + | |
| − | $ pandoc input.txt -o output.pdf
| + | * variable |
| | + | * value |
| | + | * assignment operator (=) |
| | + | * difference between variables and values |
| | + | * integers |
| | + | * print() |